Aluminum plating apparatus and method for producing aluminum film using same

ABSTRACT

The invention offers an aluminum-plating apparatus that can satisfactorily form an aluminum plating even on the surface of a base body that has a surface on which an insulating or poorly conductive metal oxide film or the like is formed. The aluminum-plating apparatus electrodeposits aluminum onto a base body by conveying the base body in a plating bath. The plating bath is divided into a first electrolysis chamber and a second electrolysis chamber by a partition plate in this order from the upstream side in the conveying direction for the base body. In the first electrolysis chamber, a negative electrode provided in the chamber is electrically connected with the base body such that the base body acts as a positive electrode. In the second electrolysis chamber, a positive electrode provided in the chamber is electrically connected with the base body such that the base body acts as a negative electrode.

TECHNICAL FIELD

The present invention relates to an aluminum-plating apparatus forelectroplating the surface of a base body with aluminum and a method ofproducing an aluminum film using the foregoing apparatus.

BACKGROUND ART

Aluminum forms a close-knit oxide film on its surface to be passivatedand thus exhibits excellent corrosion resistance. For this reason,aluminum plating is performed on the surface of a steel tape and thelike to enhance the corrosion resistance.

To perform aluminum plating on the surface of a steel tape, first, thesteel tape is conveyed continuously into a plating bath through aconductor roll. The tape runs in a positive electrode immersed in aplating liquid in the plating bath. At this moment, the steel tape iselectrically connected so as to act as a negative electrode, so thatelectrolysis occurs between the positive electrode and the steel tape,which is the negative electrode. As a result, aluminum iselectrodeposited on the surface of the steel tape to form an aluminumplating. The steel tape running in the plating liquid undergoes adirection change by a turn roll to run upward this time. In this case,also, plating is performed in relation to the positive electrode. Thesteel tape on which the aluminum plating is formed leaves the platingbath, passes another conductor roll, and is taken out of the system (thepublished Japanese patent application Tokukaihei 05-222599 (PatentLiterature 1)).

As a metallic porous body having a three-dimensional network structure,a porous body composed of aluminum holds promise as a material forincreasing the capacity of the positive electrode of a lithium-ionbattery. At present, exploiting conductivity, corrosion resistance,lightweight, and other excellent features of aluminum, a materialproduced by coating an active material such as lithium cobalt oxide onthe surface of an aluminum foil is used as the positive electrode of alithium-ion battery. When the positive electrode is formed by using theporous body composed of aluminum, it is possible to increase the surfacearea and to fill the active material even at the interior of thealuminum. As a result, even when the electrode is thickened, a decreasein the utilization rate of the active material is avoided. Consequently,the utilization rate of the active material per unit area is increased,and therefore the capacity of the positive electrode can be increased.

The present applicant has proposed a method of electroplating a resinformed body having a three-dimensional network structure with aluminumas a production method of the above-described aluminum porous body (thepublished Japanese patent application Tokukai 2012-007233 (PatentLiterature 2)). The conventional aluminum molten-salt bath is requiredto be heated to high temperature. Consequently, when the surface of aresin formed body is electroplated with aluminum, the resin cannotwithstand the high temperature and melts, which is one of the problemsin this case. However, according to the method stated in PatentLiterature 2, the mixing of an organochloride salt, such as1-ethyl-3-methylimidazolium chloride (EMIC) or 1-butylpyridiniumchloride (BPC), and aluminum chloride (AlCl₃) forms an aluminum baththat is a liquid at room temperature, thereby enabling a resin formedbody to be electroplated with aluminum. In particular, the EMIC-AlCl₃system is good in the characteristics of the liquid, so that it isuseful as an aluminum-plating liquid.

In the above-described aluminum-plated steel tape and aluminum porousbody having a three-dimensional network structure, in order to obtain asurface having excellent glossiness and to increase the thickness of thelayer of the aluminum plating, it is necessary that a base body having asurface of aluminum be further plated with aluminum.

However, as described above, an oxide film is formed on the surface ofthe aluminum. Therefore, even when it is intended to electrodepositaluminum onto the aluminum surface, electricity cannot be supplieduniformly to the surface. As a result, a plating is formed in the shapeof islands, which is a problem.

CITATION LIST Patent Literature

Patent Literature 1: the published Japanese patent applicationTokukaihei 05-222599

Patent Literature 2: the published Japanese patent application Tokukai2012-007233

SUMMARY OF INVENTION Technical Problem

In view of the above-described problem, an object of the presentinvention is to offer an aluminum-plating apparatus that cansatisfactorily form an aluminum plating even on the surface of a basebody that has a surface on which an insulating or poorly conductivemetal oxide film or the like is formed.

Solution to Problem

The present inventors have studied intensely to solve theabove-described problem and have found that it is effective to performaluminum plating after electrolytically removing, in a plating bath, anoxide film formed on the surface of a metal. Thus, the present inventionis completed. More specifically, the present invention has theconstitution described below.

(1) An aluminum-plating apparatus for electrodepositing aluminum onto abase body by conveying the base body in a plating bath. The apparatushas the following feature:

-   -   the above-described plating bath is divided into a first        electrolysis chamber and a second electrolysis chamber by a        partition plate in this order from the upstream side in a        direction that the above-described base body is conveyed;    -   in the above-described first electrolysis chamber, which is        provided with a negative electrode, the negative electrode is        electrically connected with the above-described base body in        such a way that the above-described base body acts as a positive        electrode; and    -   in the above-described second electrolysis chamber, which is        provided with a positive electrode, the positive electrode is        electrically connected with the above-described base body in        such a way that the above-described base body acts as a negative        electrode.

The aluminum-plating apparatus stated in (1) above performs reverseelectrolysis in the first electrolysis chamber. Therefore, even when aninsulating or poorly conductive metal oxide film or the like is formedon the surface of a base body, it can be removed electrolytically, sothat aluminum can be satisfactorily electrodeposited in the subsequentsecond electrolysis chamber.

(2) The aluminum-plating apparatus as stated in (1) above, the apparatushaving, at the upstream side of an entrance of the above-described firstelectrolysis chamber, a first electricity supply roller that gives anelectric potential to the above-described base body and concurrentlyconveys the base body.

The invention stated in (2) above enables the giving of an electricpotential to the base body in the vicinity of the first electrolysischamber while the base body is being conveyed.

(3) The aluminum-plating apparatus as stated in (1) or (2) above, theapparatus having, at the downstream side of an exit of theabove-described second electrolysis chamber, a second electricity supplyroller that gives an electric potential to the above-described base bodyand concurrently conveys the base body.

The invention stated in (3) above enables the giving of an electricpotential to the base body in the vicinity of the second electrolysischamber while the base body is being conveyed.

(4) The aluminum-plating apparatus as stated in any one of (1) to (3)above, in which the above-described plating bath contains a molten-saltbath composed mainly of aluminum chloride.

The invention stated in (4) above enables the use of the conventionalmolten-salt bath composed mainly of aluminum chloride and consequentlythe obtaining of a good-quality aluminum film.

(5) The aluminum-plating apparatus as stated in any one of (1) to (4)above, in which the above-described base body is a sheet formed of aresin formed body having a three-dimensional network structure that hasundergone conductive treatment.

The invention stated in (5) above enables the continuous production of aresin structure that has an aluminum film on the surface of a resinformed body having a three-dimensional network structure.

(6) An aluminum-plating apparatus, having two or more aluminum-platingapparatuses each as stated in any one of (1) to (5) above;

the apparatuses being positioned in series in a direction that theabove-described base body is conveyed.

The invention stated in (6) above enables the providing of only one setof incidental equipment, such as a supplying facility and a taking-upfacility for the base body, so that the investment for the equipment canbe reduced significantly.

(7) An aluminum-plating apparatus, having an aluminum-plating apparatus:

-   -   that is positioned at a preceding position of the        aluminum-plating apparatus as stated in any one of (1) to (6)        above, the preceding position being the most upstream position        in a direction that the above-described base body is conveyed;    -   that electrodeposits aluminum onto the above-described base body        by conveying the above-described base body in a plating bath;        and    -   that has a feature in that in the plating bath, which is        provided with a positive electrode, the positive electrode is        electrically connected with the above-described base body in        such a way that the above-described base body acts as a negative        electrode.

The invention stated in (7) above enables the use of the conventionalaluminum-plating apparatus at the most upstream position in a directionthat the base body is conveyed when the apparatus uses a base body thathas a surface on which no insulating or poorly conductive metal oxidefilm or the like is formed. In addition, only one set of incidentalequipment, such as a supplying facility and a taking-up facility for thebase body, is necessary, so that the investment for the equipment can bereduced significantly.

(8) A method of producing an aluminum film, the method electrodepositingaluminum onto a base body using the aluminum-plating apparatus as statedin any one of (1) to (7) above.

The method of producing an aluminum film stated in (8) above enables theformation of a good-quality aluminum film on the surface of a base bodyeven when the base body has a surface on which an insulating or poorlyconductive metal oxide film or the like is formed.

Advantageous Effects of Invention

The present invention can offer an aluminum-plating apparatus that cansatisfactorily form an aluminum plating even on the surface of a basebody that has a surface on which an insulating or poorly conductivemetal oxide film or the like is formed.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 is a diagram showing an example of the aluminum-plating apparatusof the present invention.

FIG. 2 is a diagram showing another example of the aluminum-platingapparatus of the present invention.

DESCRIPTION OF EMBODIMENTS

The aluminum-plating apparatus of the present invention is analuminum-plating apparatus for electrodepositing aluminum onto a basebody by conveying the base body in a plating bath. The apparatus has thefollowing feature:

-   -   the above-described plating bath is divided into a first        electrolysis chamber and a second electrolysis chamber by a        partition plate in this order from the upstream side in a        direction that the above-described base body is conveyed;    -   in the above-described first electrolysis chamber, which is        provided with a negative electrode, the negative electrode is        electrically connected with the above-described base body in        such a way that the above-described base body acts as a positive        electrode; and    -   in the above-described second electrolysis chamber, which is        provided with a positive electrode, the positive electrode is        electrically connected with the above-described base body in        such a way that the above-described base body acts as a negative        electrode.

The above-described base body is not particularly limited. However, anoutstanding effect is exerted in the case of a base body onto which theconventional aluminum-plating apparatus cannot satisfactorilyelectrodeposit aluminum, such as a metal having a metal oxide film (apassive film) on its surface. The types of the foregoing base bodyinclude a steel tape (a steel plate), an aluminum porous body having athree-dimensional network structure, a SUS plate, a Cu or Cu alloyplate, and a Zn or Zn alloy plate.

The above-described plating bath contains a plating liquid. The platingliquid is not particularly limited provided that the liquid has acomposition capable of performing electroplating with aluminum. Aluminumhas a high affinity for oxygen and has an electric potential lower thanthat of hydrogen. Consequently, it is difficult to performelectroplating in an aqueous solution-based plating bath, so that amolten-salt bath is used. A molten-salt bath composed mainly of aluminumchloride can be advantageously used.

As for the molten salt, an organic molten salt in the form of a eutecticsalt of an organohalide and an aluminum halide and an inorganic moltensalt in the form of a eutectic salt of a halogenide of an alkali metaland an aluminum halide can be used. When an organic molten-salt bath,which melts at relatively low temperature, is used, plating can beperformed without decomposing a resin formed body used as a base body,which is desirable. As for the organohalide, an imidazolium salt, apyridinium salt, and the like can be used. More specifically,1-ethyl-3-methylimdazolium chloride (EMIC) and butylpyridinium chloride(BPC) are desirable.

When moisture or oxygen intrudes into a molten salt, the molten saltdeteriorates. Therefore, it is desirable to perform plating not only ina nitrogen, argon, or other inert gas atmosphere but also in an enclosedenvironment.

As for the molten-salt bath, a molten-salt bath containing nitrogen isdesirable. When a resin formed body having a three-dimensional networkstructure is used as the above-described base body, if a salt that meltsat high temperature is used as the molten salt, the resin dissolves ordecomposes in the molten salt more quickly than the layer of platinggrows. As a result, the layer of plating cannot be formed on the surfaceof the resin formed body. In this case, an imidazolium salt bath can beadvantageously used. An imidazolium salt bath can be used even atrelatively low temperature without affecting the resin.

As the imidazolium salt, a salt containing an imidazolium cation havingan alkyl group at the 1, 3 position can be advantageously used. Inparticular, an aluminum chloride-1-ethyl-3-methylimdazolium chloride(AlCl₃-EMIC)-based molten salt is most advantageously used because ithas high stability and therefore is less likely to decompose. Platingcan be performed on urethane-resin foam, melamine-resin foam, and thelike. The temperature of the molten-salt bath is 10° C. to 100° C.,desirably 25° C. to 45° C. As the temperature decreases to lowtemperature, the range of electric-current density that enables platingis narrowed, so that it becomes difficult to perform plating on theentire surface of the resin formed body. A high temperature exceeding100° C. tends to create a problem of impairing the shape of the resinused as the base body.

When a base body having a high melting point, such as a steel tape, isused, an inorganic-salt bath can also be used as the molten salt. Theinorganic-salt bath is typically a salt of a two-constituent system ormulticonstituent system of AlCl₃—XCl (X: alkali metal). The foregoinginorganic-salt bath generally has a high melting temperature incomparison with an organic-salt bath such as an imidazolium salt bathbut has few limitations on environmental conditions such as moisture andoxygen, thereby enabling the practical use at a low cost as a whole.

To enhance the smoothness and glossiness of a film of aluminum platingformed on the surface of a base body, an additive such as xylene,benzene, toluene, and 1,10-phenanthroline may be added. In particular,1,10-phenanthroline can be advantageously used. It is desirable that theamount of addition of the above-described additive be 0.25 to 7 g/L.When the amount is 0.25 g/L or more, a sufficiently smooth film ofaluminum plating can be obtained. When 7 g/L or less, a decrease inplating efficiency can be suppressed.

In the following, a further detailed explanation of the presentinvention is given by referring to the drawing as appropriate.

FIG. 1 is a diagram showing an example of the structure of thealuminum-plating apparatus of the present invention. As shown in FIG. 1,in the aluminum-plating apparatus of the present invention, a platingbath 102 containing a plating liquid is divided into a firstelectrolysis chamber 104 and a second electrolysis chamber 105 by apartition plate 103. A base body 101 is conveyed continuously from thefirst electrolysis chamber 104 to the second electrolysis chamber 105.

The partition plate 103 is provided to electrically separate the firstelectrolysis chamber 104 and the second electrolysis chamber 105. Aninsulating partition plate can be advantageously used. For example,Teflon (registered trademark), ceramics, glass, a super engineeringplastic such as polyether ether ketone (PEEK), and a heat-resistantvinyl chloride resin can be used.

The partition plate 103 is provided with a passing aperture for the basebody. It is desirable that the passing aperture have the minimumpossible dimension only allowing the passing of the base body. Forexample, it is desirable that the passing aperture for the base bodyhave the shape of a slit.

The first electrolysis chamber 104, to which the base body 101 isconveyed initially, is provided with negative electrodes 107, which areelectrically connected in such a way that the base body 101 acts as apositive electrode in the first electrolysis chamber 104. Thisconfiguration creates electrolysis between the negative electrodes 107and the base body 101. As a result, a metal oxide film formed on thesurface of the base body 101 is electrolytically removed, so that thesurface of the metal forming the base body 101 is exposed.

The negative electrodes 107 are not particularly limited. For example,aluminum, titanium, and copper can be advantageously used.

FIG. 1 shows, as an example, the case where two negative electrodes 107are provided: one above the base body 101 and the other below.Nevertheless, the number of the negative electrodes 107 is notparticularly limited. One electrode or three or more electrodes may beemployed. The location at which the negative electrodes 107 are providedis not particularly limited. However, it is desirable to provide them ata position closest possible to the base body 101 so that theelectrolysis can occur effectively.

To cause the base body 101 to act as the positive electrode in the firstelectrolysis chamber 104, the terminal of the positive electrode of thepower source connected to the negative electrodes 107 is connected tothe base body 101. In this case, to cause the electrolysis to occureffectively, it is desirable that the base body 101 be connected to thepositive electrode at the upstream side in the vicinity of the entranceof the first electrolysis chamber 104.

FIG. 1 shows the case where a first electricity supply roller 106 isprovided at the upstream side of the entrance of the first electrolysischamber 104 and is connected to the positive electrode of the powersource. By employing this configuration, while the base body 101 isbeing continuously conveyed by the first electricity supply roller 106and a first conveying roller 110, an electric potential is given to thebase body 101 by the first electricity supply roller 106, so that thebase body 101 acts as the positive electrode in the first electrolysischamber 104. FIG. 1 shows the case where the first conveying roller 110is provided at the opposite side of the first electricity supply roller106. Nevertheless, in place of the first conveying roller 110, anelectricity supply roller connected to the positive electrode may beprovided.

The quantity of the metal oxide film to be electrolytically removed inthe first electrolysis chamber 104 can be adjusted as appropriateaccording to the quantity of the oxide film formed on the base body 101.For example, in the case where the base body is made of aluminum, thequantity of deposition or the quantity of dissolution of aluminum can beadjusted based on the following equation:

the quantity of deposition of aluminum/the quantity of dissolution ofaluminum [g]=0.3352×I [A]×t [Hr]  (Equation).

In the above equation, “I” denotes the current value and “t” denotestime. The constant 0.3352 is a constant specific to aluminum, and whenthe base body is made of another metal, the constant can be changed tothe constant specific to that metal to carry out the calculation.

Subsequently, the base body 101 whose metal oxide film is removed asdescribed above is conveyed to the second electrolysis chamber 105through the slit formed in the partition plate 103. The secondelectrolysis chamber 105 is provided with positive electrodes 109, whichare electrically connected in such a way that the base body 101 acts asa negative electrode in the second electrolysis chamber 105. Thisconfiguration creates electrolysis between the positive electrodes 109and the base body 101. As a result, aluminum is electrodeposited on thesurface of the base body 101.

As described above, the metal oxide film formed on the surface of thebase body 101 is removed in the first electrolysis chamber 104.Consequently, a uniform aluminum plating can be formed on the surface ofthe base body 101 in the second electrolysis chamber 105.

The positive electrodes 109 are not particularly limited. For example,aluminum, titanium, and copper can be advantageously used.

As in the case of the negative electrodes 107, FIG. 1 shows, as anexample, the case where two positive electrodes 109 are provided: oneabove the base body 101 and the other below. Nevertheless, the number ofthe positive electrodes 109 is not particularly limited. One electrodeor three or more electrodes may be employed. The location at which thepositive electrodes 109 are provided is not particularly limited.However, it is desirable to provide them at a position closest possibleto the base body 101 so that the electrolysis can occur effectively.

To cause the base body 101 to act as the negative electrode in thesecond electrolysis chamber 105, the terminal of the negative electrodeof the power source connected to the positive electrodes 109 isconnected to the base body 101. In this case, to cause the electrolysisto occur effectively, it is desirable that the base body 101 beconnected to the negative electrode at the downstream side in thevicinity of the exit of the second electrolysis chamber 105.

FIG. 1 shows the case where a second electricity supply roller 108 isprovided at the downstream side of the exit of the second electrolysischamber 105 and is connected to the negative electrode of the powersource. By employing this configuration, while the base body 101 isbeing continuously conveyed by the second electricity supply roller 108and a second conveying roller 111, an electric potential is given to thebase body 101 by the second electricity supply roller 108, so that thebase body 101 acts as the negative electrode in the second electrolysischamber 105. FIG. 1 shows the case where the second conveying roller 111is provided at the opposite side of the second electricity supply roller108. Nevertheless, in place of the second conveying roller 111, anelectricity supply roller connected to the negative electrode may beprovided.

The quantity of the aluminum to be deposited in the second electrolysischamber 105 can be calculated by using the above-described equation.Consequently, the current value and time can be adjusted in such a waythat a desired quantity of aluminum is electrodeposited on the surfaceof the base body 101. The time can be adjusted by changing the conveyingspeed for the base body 101.

As described above, by using the aluminum-plating apparatus of thepresent invention, an aluminum plating can be satisfactorily formed evenon the surface of a base body that has a surface on which an insulatingor poorly conductive metal oxide film or the like is formed.

In the case where aluminum plating is performed on a long base body suchas a steel tape and a sheet composed of a resin formed body having athree-dimensional network structure, the use of the aluminum-platingapparatus of the present invention can effectively produce a product byincreasing the line speed.

In the case of the conventional aluminum-plating apparatus equipped withone plating bath, when it is intended to increase the productioncapacity by increasing the line speed, it can be conceived to increasethe length of the positive electrode. For example, when the plating isperformed vertically, the plating bath is deepened, and when the platingis performed horizontally, the plating bath is lengthened. Actually,however, the length of the positive electrode effective for the platinghas a limitation. More specifically, although the plating is performedat a high current density at the position close to the conductor roll,the plating is not performed at the position far from the conductorroll. Consequently, in an apparatus equipped with one plating bath, theincrease in line speed has a limitation, so that the production capacitycannot be increased.

For that reason, it can be conceived to increase the line speed byconstituting the plating bath with two or more baths. However, even whentwo or more conventional plating apparatuses are installed in tandem tocarry out continuous operation, in the case of a metal that is likely toform an oxide film on its surface, such as aluminum, the film formed inthe plating bath in the preceding position cannot be satisfactorilyplated with aluminum, which is a problem. More specifically, an oxidefilm is formed on the surface of aluminum at the space between theplating baths. When an oxide film is formed, aluminum is deposited inthe form of islands. In other words, plating cannot be performedsatisfactorily. Even when the space between the plating baths is filledwith an N₂ or other inert atmosphere, oxygen cannot be removedcompletely and remains at an amount on the order of ppm. Even whenaluminum is exposed to such a minute amount of oxygen as describedabove, an oxide film (a passive film) is formed on the surface ofaluminum.

To evade the above-described problem, the aluminum-plating apparatus ofthe present invention can remove, in the first electrolysis chamber, anoxide film formed on the surface of aluminum. Consequently, when two ormore aluminum-plating apparatuses are provided in series in theconveying direction for the base body, the second and subsequent baths,also, can form a smooth and good-quality aluminum plating. By using analuminum-plating apparatus in which two or more aluminum-platingapparatuses described above are provided in series in the conveyingdirection for the base body, the line speed of the base body can beincreased and hence the production efficiency of the product can beincreased. Because the foregoing aluminum-plating apparatus performsaluminum plating continuously using multiple aluminum-platingapparatuses, only one set of incidental equipment, such as a supplyingfacility and a taking-up facility for the base body, is necessary, sothat the investment for the equipment can be reduced significantly.

The number of aluminum apparatuses provided in series is notparticularly limited. The number can be selected as appropriateaccording to the purpose, such as the thickness of a layer of aluminumplating to be formed. For example, when a resin formed body having athree-dimensional network structure is used as the base body, theproviding of 2 to 20 or so aluminum-plating apparatuses can effectivelyproduce an aluminum porous body.

When a resin formed body having a three-dimensional network structurehaving undergone conductive treatment by coating carbon, for example, isused as the base body, a conventional aluminum-plating apparatus may beprovided at a preceding positon of the above-described aluminum-platingapparatus of the present invention, the preceding positon being the mostupstream position in the conveying direction for the base body. As forthe conventional aluminum-plating apparatus, an aluminum-platingapparatus described below can be advantageously used. Thealuminum-plating apparatus electrodeposits aluminum onto the base bodyby passing the base body 101 through the plating bath 202 as shown inFIG. 2 and has a feature in that in the plating bath 202, positiveelectrodes 209 provided in the plating bath 202 are electricallyconnected with the above-described base body 101 in such a way that theabove-described base body 101 acts as a negative electrode.

In other words, the aluminum-plating apparatus of the present inventionhas an aluminum-plating apparatus:

-   -   that is positioned at a preceding positon of the above-described        aluminum-plating apparatus, the preceding positon being the most        upstream position in a direction that the above-described base        body is conveyed;    -   that electrodeposits aluminum onto the above-described base body        by conveying the above-described base body in a plating bath;        and    -   that has a feature in that in the plating bath, which is        provided with a positive electrode, the positive electrode is        electrically connected with the above-described base body in        such a way that the above-described base body acts as a negative        electrode.        By performing aluminum plating by placing the above-described        aluminum-plating apparatus of the present invention, which is        provided with the first electrolysis chamber that performs        reverse electrolysis, in series with the second or subsequent        aluminum-plating apparatus in the aluminum-plating apparatuses        arranged in series as described above, a uniform and        good-quality aluminum plating can be formed on the base body        effectively. In addition, as described above, the        aluminum-plating apparatus of the present invention enables the        providing of only one set of incidental equipment, such as a        supplying facility and a taking-up facility for the base body,        so that the investment for the equipment can be reduced        significantly.

EXAMPLES

In the following, a further detailed explanation of the presentinvention is given based on examples. These examples are illustrativeand not limit the aluminum-plating apparatus and the like of the presentinvention. The scope of the present invention is shown by the scope ofthe claims and covers all revisions and modifications included withinthe meaning and scope equivalent to the scope of the claims.

Example 1

Ten aluminum apparatuses of the present invention shown in FIG. 1 wereplaced in series to form a film of aluminum plating on a base body.

Base Body

As the base body, a resin formed body was used that had athree-dimensional network structure having a surface on which analuminum film was formed by the sputtering process.

As the resin formed body having a three-dimensional network structure, afoamed-urethane resin formed body having a porosity of 95%, the numberof pores (the number of cells) per inch of about 50, a pore diameter ofabout 550 μm, a width of 500 mm, and a thickness of 1 mm was used.Conductive treatment was performed by forming an aluminum film having acoating weight of 10 g/m² on the foamed-urethane resin formed body bythe sputtering process.

It was confirmed that an aluminum oxide film of 30 nm was formed in thealuminum film on the surface of the resin formed body.

Aluminum-Plating Apparatus

Ten aluminum apparatuses of the present invention shown in FIG. 1 wereprepared to be placed in series. The space between the aluminum-platingapparatuses was filled with nitrogen to form an inert atmosphere. Therotation speed of the roller was adjusted in such a way that the linespeed of the base body to be conveyed became 0.1 to 1.0 m/min. Thestructure of the individual aluminum apparatus is described below.

Molten-Salt Bath

A molten-salt bath having a composition of 33-mol % EMIC and 67-mol %AlCl₃ was produced by mixing them in a nitrogen atmosphere. In addition,1,10-phenanthroline was added such that it had a concentration of 0.5g/L.

Furthermore, nitrogen was introduced into the plating liquid to preventthe formation of an oxide film during the electrodepositing of aluminum.

Partition Plate

A partition plate made of Teflon (registered trademark) was placed inthe plating bath to partition the plating bath into a first electrolysischamber and a second electrolysis chamber. A partition plate wasprovided with a slit, which had a width of 560 mm and a height of 5 mm,to be used as a passing aperture for the base body.

First Electricity Supply Roller

A first electricity supply roller made of aluminum was used, the centerof the roller being connected to the terminal of the positive electrodeof a power source.

Negative Electrode

Negative electrodes made of aluminum were placed in the firstelectrolysis chamber. As shown in FIG. 1, the negative electrodes wereplaced at two positions: one above the base body and the other below.

First Electrolysis Chamber

To create electrolysis between the base body and the negative electrodesin the first electrolysis chamber, a current density was set at 10A/dm².

Second Electricity Supply Roller

A second electricity supply roller made of aluminum was used, the centerof the roller being connected to the terminal of the negative electrodeof a power source.

Positive Electrode

Positive electrodes made of aluminum were placed in the secondelectrolysis chamber. As shown in FIG. 1, the positive electrodes wereplaced at two positions: one above the base body and the other below.

Second Electrolysis Chamber

To create electrolysis between the base body and the positive electrodesin the second electrolysis chamber, a current density was set at 5A/dm².

The base body having undergone conductive treatment as described abovewas conveyed continuously into the ten aluminum apparatuses each havingthe above-described structure to form a film of aluminum plating on thesurface of the base body. This operation formed an aluminum film of 10μm on the surface of the base body. The formed film of plating was auniform and good-quality film.

As described above, it was confirmed that even when the operation uses abase body that has a surface on which an aluminum oxide film is formed,the use of the aluminum-plating apparatus of the present invention canfurther form a good-quality film of aluminum plating.

Example 2

As shown in FIG. 2, a conventional aluminum-plating apparatus was placedat the most upstream side in the conveying direction for the base body.Nine aluminum apparatuses of the present invention used in Example 1were placed in series at the downstream side of the above-describedconventional aluminum-plating apparatus to form a film of aluminumplating on a base body.

Base Body

A resin formed body having the same three-dimensional network structureas that employed in Example 1 was used.

Conductive treatment of the resin formed body was carried out by coatinga carbon paint as a conductive paint on the surface of a resinous porousbody. The carbon paint contained 25% carbon particles, a resin binder,an introfier, and an antifoaming agent. The carbon black had a particlediameter of 0.5 μm.

Aluminum-Plating Apparatus

The conventional aluminum-plating apparatus placed at the most upstreamside in the conveying direction for the base body had the same structureas that of the second electrolysis chamber in the aluminum-platingapparatus used in Example 1. More specifically, the plating liquid, theelectricity supply roller, and the positive electrodes respectively hadthe same structure as that of the plating liquid, the second electricitysupply roller, and the positive electrodes all used in Example 1.

The second and subsequent aluminum-plating apparatuses had the samestructure as that of the aluminum-plating apparatuses used in Example 1.Nine apparatuses as described above were placed in series.

Observation of the base body having a surface on which a film ofaluminum plating was formed revealed that an aluminum film of 10 μm wasformed on the surface of the base body and that the formed film ofplating was a uniform and good-quality film.

Comparative Example 1

A film of aluminum plating was formed on the surface of a base bodythrough the same procedure as that used in Example 1, except that as thealuminum-plating apparatus, 10 conventional aluminum-plating apparatuseswere used by placing them in series. As for the conventionalaluminum-plating apparatuses, the aluminum-plating apparatus placed atthe most upstream side in Example 2 were used. As with Example 1, thespace between the aluminum-plating apparatuses was filled with nitrogento form an inert atmosphere.

Observation of the film of aluminum plating formed on the surface of thebase body revealed that the deposition created the shape of islands andthat the film was inferior in quality to the film formed by using theapparatus of Example 1.

Comparative Example 2

A film of aluminum plating was formed on the surface of a base bodythrough the same procedure as that used in Example 2, except that as thealuminum-plating apparatus, 10 conventional aluminum-plating apparatuseswere used by placing them in series. As for the conventionalaluminum-plating apparatuses, the aluminum-plating apparatus placed atthe most upstream side in Example 2 were used. As with Example 2, thespace between the aluminum-plating apparatuses was filled with nitrogento form an inert atmosphere.

Observation of the film of aluminum plating formed on the surface of thebase body revealed that the deposition created the shape of islands andthat the film was inferior in quality to the film formed by using theapparatus of Example 2.

REFERENCE SIGNS LIST

-   101: Base body-   102: Plating bath-   103: Partition plate-   104: First electrolysis chamber-   105: Second electrolysis chamber-   106: First electricity supply roller-   107: Negative electrode-   108: Second electricity supply roller-   109: Positive electrode-   110: Second conveying roller-   111: Second conveying roller-   202: Plating bath-   208: Electricity supply roller-   209: Positive electrode

1. An aluminum-plating apparatus for electrodepositing aluminum onto abase body by conveying the base body in a plating bath, the apparatushaving a feature in that: the plating bath is divided into a firstelectrolysis chamber and a second electrolysis chamber by a partitionplate in this order from the upstream side in a direction that the basebody is conveyed; in the first electrolysis chamber, which is providedwith a negative electrode, the negative electrode is electricallyconnected with the base body in such a way that the base body acts as apositive electrode; and in the second electrolysis chamber, which isprovided with a positive electrode, the positive electrode iselectrically connected with the base body in such a way that the basebody acts as a negative electrode.
 2. The aluminum-plating apparatus asdefined by claim 1, the apparatus comprising, at the upstream side of anentrance of the first electrolysis chamber, a first electricity supplyroller that gives an electric potential to the base body andconcurrently conveys the base body.
 3. The aluminum-plating apparatus asdefined by claim 1, the apparatus comprising, at the downstream side ofan exit of the second electrolysis chamber, a second electricity supplyroller that gives an electric potential to the base body andconcurrently conveys the base body.
 4. The aluminum-plating apparatus asdefined by claim 1, wherein the plating bath contains a molten-salt bathcomposed mainly of aluminum chloride.
 5. The aluminum-plating apparatusas defined by claim 1, wherein the base body is a sheet composed of aresin formed body having a three-dimensional network structure that hasundergone conductive treatment.
 6. An aluminum-plating apparatus,comprising two or more aluminum-plating apparatuses each as defined byclaim 1; the apparatuses being positioned in series in a direction thatthe base body is conveyed.
 7. An aluminum-plating apparatus, comprisingan aluminum-plating apparatus: that is positioned at a preceding positonof the aluminum-plating apparatus as defined by claim 1, the precedingpositon being the most upstream position in a direction that the basebody is conveyed; that electrodeposits aluminum onto the base body byconveying the base body in a plating bath; and that has a feature inthat in the plating bath, which is provided with a positive electrode,the positive electrode is electrically connected with the base body insuch a way that the base body acts as a negative electrode.
 8. A methodof producing an aluminum film, the method electrodepositing aluminumonto a base body using the aluminum-plating apparatus as defined byclaim 1.